Experimental investigation on the change of pull-off force between bulk particulate material and an elastic polymeric filter fiber.

ABSTRACT

HYPOTHESIS: Adhesion between particles and a filter fiber is an important process of the filtration as it dictates the process of separation and in the following the detachment process of particles during filter regeneration. In addition to the shear stress that a new polymeric stretchable filter fiber implements into the particulate structure, the elongation of the substrate (fiber) is also expected to cause a structural change in the surface of the polymer. Thus, the changed contact area and surface energy could affect the adhesion force between particles and fibers. EXPERIMENTS Systematic measurements of adhesion forces between a single particle and the stretchable substrate were performed using Atomic Force Microscope (AFM). The substrate surface characteristics (roughness) was changed directly beneath the modified measurement head using piezo-motors to achieve stepless elongation state. Polystyrene particles and particles made of Spheriglass were applied. FINDINGS: In the experiments, a reduced adhesion force between the particles and the filter fiber was found for a new high range of substrate roughness and peak-to-peak distance, in which the Rabinovich model has not been used before [1]. Further, the influence of high and low energy surface particulate material was evaluated to understand the detachment process in the new real adaptive filter and in DEM-simulation.